Key detachment device



April 3, 1951 J. MULLAN KEY DETACHMENT DEVICE Filed April 9. 1946 V 7 2Gl A. E N. T L A N il 4. r!` 2 E 3 o 7. l l l j l 7 H l 0 2 o 8 0 3 23/1 y TL/\ Nun@ hum/Y.

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Patented Apr. 3, 1951 UNITED STATES PATENT OFFICEv KEY DETACHMENTDEVICE.

Joseph Mullan, Baltimore, Md.

Application April 9, 1946, Serial No. 660,729

This invention relates to locks and more particularly to an adjunct tokeys tending to displace same from a lock when the key is placed in anunlocked position therein.

The conventional key used in a lock has the disadvantage of staying inthe lock /when the key is in the unlocked position. In the use ofautomobiles, keysrare employedto switch on and off the ignition, and arefrequently left in the switch by the drivers after they have turned oithe ignition, and left the cars. This leaving 'of the keys in the'ignition lock has proven to be of considerable value to those lwho wantto operate the automobiles in an unauthorized manner, and is consideredpoor practice. However many people still leave the keys in the ignitionlocks inadvertently or carelessly and thereby offer an inducement tounauthorized persons to use their automobiles. House locks with theirkeys therein ofer opportunities for the unlocking of the doors byypersons equipped with certain facilities for doing so, which they couldnot do without them.

It is an object of this invention to provide a new and improved adjunctto a key or key detachment that will avoid one or more of thedisadvantages and limitations of the prior art.

Another object of the present invention is to provide a new and improvedadjunct to a key or key detachment that will positively provide for theremoval of the key from the lock when.

the key is operated to unlocked position.

For a better understanding of this invention and for other objectsthereof reference is had to the attached drawings and followingdescription, While the scope of the invention is particularly pointedout in the claims.

In the drawings:

Figure 1 is a plan view of a key detachment device embodying thisinvention,

Figure 2 is an end view of Figure l,

Figure 3 is a sectional view taken along line 3-3 of Figure 1,

Figure 4 is a view of the parts ready for assembly,A

Figure 5 is an end view looking in the direction of arrows 5-5 of Figure4,

Figure 6 is an end View looking in the direction ofy arrows 6 6 ofFigure 4, and

Figure 7 is an end view looking in the direction of arrows 'I-I ofFigure 4.

Similar reference characters refer to similar parts throughout thedrawings.

In the drawings, a key I 0 of conventional formY is indicated inl dottedoutline with a key detach- 3 claims. (o1. 711-414) ment device IIarranged to hold it. The detachment consists of a guiding member I2 ofhollow cylindrical form having longitudinal slots I3 in its side wallsto guide the movement of the key head therein. Its front end portion I 4is provided with a rectangular hole I5 arranged to fit the transversesection I 6 of the key and guide it in its travel. A collar I'I is slidover the hollow guiding member I2 and is prevented from turning thereonby lips I8 which slide in the longitudinal slots I3. The face of thecollar has a transverse slot I9 in its face to position the key headtherein, The rear portion 20 of the detachment device is cylindrical inform and is provided With an inner cylindrical slot 2| into which ispositioned the end of the hollow cylindrical guiding member I2. Thecenter hole 22 of the rear portion provides guide means to encompass thediameter of a spring 23. A slot 24 is used to anchor one end 25 of thespring and the other end 26 is attached to the hole 2'I of the key I0 todra-w the key back into the detachment device when the ignition switchis unlocked. A transverse hole 28 in the rear portion 20 is aligned withthe hole 29 in the hollow cylindrical side walls of the guiding memberI2. A exible detachable chain 30 is passed through the holes 28 in therear portion 20 then through the holes 29 in the hollow cylindricalguiding member I2 and through the anchor end 25 of the spring 23.

The device is preferably .assembled as follows: The key I0 is slid intothe slot I3 of the hollow cylindrical guiding member I2, the collar IIis then slid over the cylindrical guiding member, the spring end 26 isthen attached into the hole 21 in the key, the end of the hollowcylindrical guiding member is slid into the inner cylindrical slot 2l ofthe rear portion 20 until the holes 29 align with the holes 28 and thespring end 25 and the exible chain 30 is positioned and the device isready for use.

In the use of the device the key head is pressed forward with thefingers, stretching the spring 23 until the tooth portion of the keyenters the ignition switch properly, and the whole device is turned tooperate the lock. The turning of the lock holds the key I 0 in place inthe lock and prevents its removal. When the key is operated to unlockthe lock, its key shank becomes aligned with the hole in the lockingmechanism and under the pull of the spring, the key is drawn out of thelock and back into the device, and will fall to the oor of the car, outof contact with the ignition mechanism. Although the use of the keydetachment has been described as being 3 used with automobiles toprevent their theft, caused by leaving the key in the ignition lock, itcan be readily seen that its application is not to be restricted to thisuse, as it can also be used with any other type of lock that uses a keyfor its manipulation.

While but one general form of the invention is shown in the drawings anddescribed in the specifications, it is not desired to limit thisapplication for patent to this particular form or in any other wayotherwise than limited by the scope thereof, as it is appreciated thatother` forms of construction could be made that would use the sameprinciples and come within the scope of the appended claims:

Having thus described the invention what is claimed is:

1. A key detachment device comprising a housing having a cylindricalchamber therein, a tension spring in vsaid chamber having one endfpos'itively anchored to said housing, a tubular cylindrical guidingmember keyed to said housing and having its interior in communication`with the aforesaid chamber, said guiding member having oppositelongitudinal slots through its wall adapted to engage the head of a key,land the free end of 'said spring adapted to be vsecured. to the head ofthe key, whereby said spring will be stretched when the key is engagedhousing having a cylindrical chamber therein, a tension spring in saidchamber having one end secured to said housing, said housing also havingan annular chamber therein, a tubular guiding member having longitudinalslots adapted to engage the head of a key placed within said guidingmember, said guiding member having a portion extending within theannular chamber of said housing, a collar slidably mounted on saidtubular guiding member, said collar having locking means engaging saidguiding member and other locking means adapted to engage the head of thekey, and the free end of said spring adapted to be secured to the headof the key, whereby said spring will be stretched when the key isengaged in a lock and said spring will retract the key within saidguidingmember when v the key'is free of the lock.

in a lock and said spring will retract the key :.30

within said guiding member when the key is free from the lock. y

2. A key detachment device comprising a 3. A key detachment device asset forth in claim 2, wherein said guiding member has a slot at its freeend to guide the shank of the key in its travel.

JOSEPH MULLAN.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 1,745,836 Miller et al. Feb. 4,1930 2,076,895 Johnston Apr. 13, 1937

